CLEVELAND, Ohio — The so-called heartbeat bill would outlaw abortions in Ohio before many women know they’re pregnant. It would be one of the strictest abortion laws in the country, designed to trigger a Supreme Court battle that could knock down Roe v. Wade.

The bill on Gov. John Kasich’s desk would prohibit abortion once doctors can detect a fetal heartbeat, normally around six weeks into a pregnancy. That’s whether doctors look for the heartbeat with an abdominal or transvaginal ultrasound.

For context, by the time a woman misses her period, she’s generally considered four weeks pregnant. So if a woman has a perfect 28-day menstrual cycle, she would have about two weeks to discover she’s pregnant, decide to have an abortion and schedule appointments with an abortion clinic.

Abortion advocates and medical professionals say the quick timeline would make it impossible for most women to get an abortion.

“This legislation is 100-percent crafted to be an arrow that goes at the heart of Roe v. Wade,” said Republican Rep. Christina Hagan, the primary sponsor of the legislation.

Kasich said he would make an announcement by Thursday about whether he would veto or approve the heartbeat bill. The out-going governor previously vetoed a different “heartbeat bill” in 2016. He didn’t indicate Wednesday which way he would go this time.

Even if the bill doesn’t become law this year, though, both advocates and opponents of the bill believe this issue is likely to resurface.

This is at least the fourth iteration of the heartbeat bill, according to the Ohio Legislative Service Commission, and at least the second time such a bill has passed both chambers of the Ohio Legislature.

“It could radically change what the legal landscape is for bodily autonomy, for abortion rights, for privacy rights,” said Kellie Copeland, executive director of NARAL Pro-Choice. “It could be really far reaching beyond even Ohio.”

Here’s everything you need to know about the heartbeat bill.

If the heartbeat bill becomes law, how would it affect women’s access to abortion?

Very few women would be able to access abortion in Ohio if the heartbeat bill took effect, experts say. The average patient seeking an abortion comes in to a clinic after the six-week benchmark.

Currently, abortion is legal in Ohio up to 22 weeks. There are seven abortion clinics across the state, only in the state’s major cities.

Is it likely that the heartbeat bill will become law?

Kasich, whose term ends Jan. 14, has until just after Christmas to decide to veto or approve the bill.

When a governor vetoes or line-item vetoes a bill, it can still become law if the legislature overrides the governor’s decision. So the Ohio legislature would need to reconvene before the end of the year to override Kasich’s veto, with three-fifths of the Ohio House (60 of 99 representatives) and the Ohio Senate (20 of 33 senators).

Legislators could reintroduce the bill and vote again next session, beginning Jan. 7. Then the bill could go to DeWine.

Why do legal experts say the heartbeat bill is unconstitutional?

The bill directly contradicts a longstanding Supreme Court precedent.

The Supreme Court case Casey v. Planned Parenthood in 1992 said that a woman can decide to end her pregnancy prior to viability, defined as being when the fetus can survive outside the womb, with some restrictions. After the fetus becomes viable, a state can ban abortion, except in cases where the pregnant woman’s life or health is at risk.

The heartbeat bill would ban abortion once the fetal heartbeat is detectable, well before the fetus is viable.

What kind of legal battle could the heartbeat bill trigger?

If the heartbeat bill became law, abortions rights advocates would file a federal lawsuit. The law likely wouldn’t take effect until the legal battle was resolved. Lower courts would likely rule in favor of the challenge, because the heartbeat bill does not align with the current precedent.

A similar example? The state ban in 2016 on abortions after a prenatal screening or test shows the fetus likely has Down Syndrome. That case was challenged in court, and was blocked from taking effect until the legal battle is resolved. In March a federal judge found the law to be unconstitutional. The case has been appealed to the Sixth Circuit Court of Appeals, where opening arguments are set to begin on Jan. 30.

Ohio isn’t the first state to try to pass a heartbeat bill, but the political atmosphere has changed. The balance of the Supreme Court shifted right when Justice Anthony Kennedy retired this year and was replaced by Justice Brett Kavanaugh, a staunch conservative.

Hagan said she believes the changes in the Supreme Court have made some Republicans more confident that the bill could withstand a court challenge.

Legal scholars caution against predicting which cases the Supreme Court chooses to take. The court declined a recent case involving Planned Parenthood and Medicaid funding. And none of the Supreme Court Justices want the court to be politicized, said Marc Spindelman, a law professor at Ohio State University’s Moritz College of Law.

But if the heartbeat bill became law and was challenged, the case would be teed up for the Supreme Court to make a new decision about abortion access.

“It’s very, very clearly unconstitutional,” said Case Western Reserve University professor Jessie Hill, who represents Preterm abortion clinic in the Down Syndrome abortion ban challenge. “The legislators know that. They are trying to mount a challenge to Roe v. Wade. That’s the game right now.”

How does the heartbeat bill compare what other states are doing?

If the heartbeat bill became law, it would be one of the strictest anti-abortion regulations across the country.

Ohio would become the fourth state to pass this kind of legislation, joining Arkansas, North Dakota and Iowa. Heartbeat bills passed in those states have been halted in court.